Clothes washing machine and hydraulic transmission



G. E. FLINN 3,330,138

CLOTHES WASHING MACHINE AND HYDRAULIC TRANSMISSION July 11, 1967 5 Sheets-Sheet 1 Filed Dec.

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Y 76 fi/ezzz or eozgqe inzz iwf S 200 PSI GEAR PUMP ELECTR/CAL CONTROL CIRCUIT July 11', 1967 E FUNN 3,330,133

CLOTHES WASHING MACHINE? AND HYDRAULIC TRANSMISSION Filed Dec. 13, 1965 5 Sheets-Sheet 2 95 46 4; a5 i F2 1% JP/N CYCLE 392 Jlc" SPIN M T 65/71? PI/MP ELEC TR/CAL CONTROL CIRCUIT i v I 9'39 in Agra/622501" July 11, 1967 G- E. FLINN 3,330,138

CLOTHES WASHING MACHINE AND HYDRAULIC TRANSMISSION Filed Dec. 15, 1965 5 Sheets-Sheet 3 v fi/ezz Z01 Geozye I 71/117222 '7 PM??? v Gib y United States Patent 3,330,138 CLOTHES WASHING MACHINE AND HYDRAULIC TRANSMISSION George E. Flinn, Muncie, Ind., assignor to Borg-Warner Corporation, Chicago, 11]., a corporation of Illinois Filed Dec. 13, 1965, Ser. No. 513,262 Claims. (Cl. 6823) This invention relates to a hydraulic transmission. More particularly this invention relates to a hydraulic transmission particularly adapted for use in an automatic clothes washer although use in other machines would be contemplated.

It is an object of this invention to provide an improved transmission for the clothes basket and agitator drive of an automatic clothes washer comprising a fluid pump operable in two directions of rotation in combination with a control system adapted to deliver fluid to a fluid motor to spin the clothes basked when the pump is operated in one direction and operative to deliver fluid pressure to a fluid motor adapted to oscillate the agitator of the washer when the pump is operated in the reverse direction of rotation. In accordance with the invention an improved form of control for a hydraulic transmission for a Washer is presented in that the speed of the spinning of the clothes basket is controlled by a manually adjustable means to control the exhaust fluid from the spin motor and the speed of agitation of the agitator of the clothes Washer is controlled by a manually operated means controlling the exhaust fluid pressure from the agitator fluid motor.

The invention consists of the novel constructions, arrangements and devices to be hereinafter described and claimed for carrying out the above stated objects and such other objects as will appear from the following description of the preferred embodiment of the invention illustrated with reference to the accompanying drawings, wherein:

FIGURE 1 is a schematic view of a hydraulic transmission for a clothes washer during the agitate cycle embodying the principles of the invention;

FIGURE 2 is a schematic view showing the hydraulic transmission during the spin cycle; and

FIGURE 3 is a cross section through the transmission in an automatic washer installation.

Referring to FIGURE 1 the hydraulic transmission 10 is schematically illustrated for driving the clothes basket 11 and the agitator 12 of an automatic clothes Washer. The hydraulic transmission has the following major components: (1) a positive displacement gear-type pump 15, (2) a positive displacement fluid motor of the gear-type 16 which is adapted to drive a hollow shaft 11a (shown schematically in FIGURE 1) connected to the clothes basket of the automatic Washer for driving same and (3) an agitating fluid motor 17 adapted to be connected to drive the agitator 12 with an oscillating type of motion.

A reversible electric motor 18 is connected to the pump and thereby adapted to drive the pump 15 in either direction of rotation. The arrows around one of the gears of the pump 15 show the direction of rotation of one of the gear elements for either the spin cycle of the washer in which fluid pressure will be supplied to the fluid circuit for the fluid motor 16 or the agitate cycle of the washer for which fluid pressure will be supplied to the fluid circuit for the agitate fluid motor 17. A fluid sump 19 is provided to contain the fluid for transmission 10.

A fluid conduit 20 connects the pump 15 with the spin motor 16 and a fluid conduit 21 connects the fluid pump 15 with the agitate fluid motor 17. Conduit 21 is con- ICC nected to the sump 19 by a check valve 19a which allows fluid flow only in the direction from sump 19 into conduit 21. Over pressure relief valves 22 and 23 are provided for the pump 15.

Relief valve 22 is connected by a conduit 27 to fluid conduit 20-. Relief valve 22 is also connected to a fluid conduit 21 by a conduit 28.

Relief valve 23 is connected to fluid conduit 21 by conduit 32 and to fluid conduit 20 by conduit 27.

Within the fluid circuit for the spin cycle of the clothes Washer along with the fluid motor 16 for spinning the clothes basket there is provided a stop valve 35 and a manually operable variable restriction exhaust valve 36.

Stop valve 35 includes a valve body 38 having ports 39, 40, 41 and 42. A valve spool 43 is slidable in body 38 which has lands 44 and 45 thereon separated by groove 46. A spring 47 urges the valve spool 43 to the left as viewed in FIGURE 1.

Exhaust fluid pressure from fluid motor 16 is connected to be delivered to port 41 of valve 35 by conduit 50. Port 39 is connected to the fluid supply conduit 20 to the fluid motor 16 by conduit 51. Port 40 of the valve 25 is connected to the sump by conduit 52 including restriction 53. Port 42 of valve 35 is connected to the manually operable exhaust valve 36 by conduit 54. Conduit 54 is connected to the sump through a restriction 55. Conduit 51 is connected to the sump by check valve 56 which allows fluid flow only in the direction from the sump into conduit 51.

Exhaust valve 36 is schematically represented and constitutes a manually adjustable valve of the needle valve type including a tapered opening 60 which can be variably restricted by a needle 61 which is manually adjustable to allow adjustment of the flow from conduit 54. Fluid passing through valve 36 is returned to the sump 19 through a conduit 62.

The fluid circuit for the agitate cycle of the automatic washer includes, in addition to the agitate fluid motor 17 and the pressure supply conduit 21, a direction valve and a manually operable variable restriction exhaust valve 71. v The agitate fluid motor 17 includes a body 74 having a chamber 75 having a vane 76 therein which will be oscillated by the action of the fluid pressure supplied to the chamber 75. The vane 76 is connected in a wash machine installation to drive the agitator 12 of the washing machine.

The motor 17 also includes a pair of pins 77 and 78 slidably mounted in a body 74 which engage with a rockable arm 79 which is pivoted at 80. The chamber 75 has ports 81 and 82 therein at opposite sides thereof through which fluid pressure may be supplied from the direction valve 70.

The direction valve 70 includes a valve body 85 having a spool 86 slidable therein. The valve spool 86 has lands 87, 88 and 89 thereon. Lands 87 and 88 are separated by a groove 90. Lands 88 and 89 are separated by a groove 91. The valve spool 86 also includes grooves 92, 93 and 94. A ball detent mechanism is provided constituting a ball 95 urged by spring 96 into engagement with either the groove 92 or 93 depending upon the position of the valve spool 86. The spool groove 94 is engaged by an end portion 97 on the rocking arm 79.

The valve body further includes ports 101, 102, 103, 104, and 106. Port 102 is connected to conduit 21. Ports 101 and 106 are interconnected with port 82 of the agitate motor 17 by a conduit 110. Ports 103 and 104 are interconnected with the port 81 of the agitate motor 17 by a conduit 111. Port 105 is connected to the exhaust valve 71 by means of a conduit 112. Conduit 112 is connected to the sump 19 through a conduit 113 having a restriction 114 therein.

Exhaust valve 71 is schematically illustrated and constitutes a manually adjustable valve of the needle valve type including a tapered opening 120 which can be variably restricted by aneedle 121 which is manually adjustable to vary the flow from conduit 112. Fluid passing through valve 71 is returned to sump 19 by a conduit 122.'

A basket brake 125 which eomprises a cylinder 126 is connected to fluid conduit 21 having a piston 127 therein; A spring 130 urges piston 127 to the left as viewed in FIGURE 1. Piston 127 has a pawl or projection 128 thereon engageahle in one of a plurality of matching notches in a disc 129 provided on the clothes basket 11 so that when fluid pressure exists in conduit 21 piston 127 will engage the pawl 128 to hold the basket 11 stationary.

Also connected to the fluid conduit 21 is a fluid pressure actuated clutch 135. Positive clutch teeth 136 are provided on a shaft 134 drivingly connected to agitator 12. Mating positive clutch teeth 137 are provided-on a fluid piston 138 which is mounted in a fluid cylinder 139. Fluid cylinder 139 receives fluid pressure from conduit 21. A spring 140 urges piston 138 toward a disengaged position of clutch teeth 137-136. The teeth 136 and 137 are engageable to provide a driving connection between agitator 12 and the oscillating vane 76 of the agitator motor 17. Vane 76 is drivingly connected to piston 138 as schematically illustrated.

The operation of the hydraulic transmission as described is as follows: when the fluid pump is rotated by V V the motor 18 in the direction indicated by the arrow noted spin, fluid pressure will be drawn from the sump through check valve 19a into conduit 21 and squeezed out between the teeth of the pump into conduit to the fluid circuit for spin motor 16. Fluid pressure is thus supplied to the fluid motor 16 which is connected to drive the clothes basket 11 of the automatic washer through shaft 11a and the machine will begin the spin cycle as illustrated in FIGURE 2. The pressure in conduit 20 is imposed on over pressure relief 23 which would, for example, be set open at 150 p.s.i. so that if the fluid pressure in the conduit 20 exceeded 150 p.s.i. the relief valve 23 would open to'relieve the fluid pressure and allow pressure to flow into conduit 21 which is now acting as the fluid pressure inlet supply passage for pump 15.

Thus as fluid pressure is supplied to the fluid motor 16 of positive displacement the gears of the fluid motor will rotate and rotate the clothes basket at a high rpm. to spin the water from the clothes.

Exhaust fluid pressure from the fluid motor 16.flows through conduit 50 and port41 into the groove 46 of the valve 35. Since fluid pressure from the pump is imposed through conduit 51 and port 39 on the left end of the valve spool 43, the valve spool 43 will be moved to the right against the force of spring 47 to the position illustrated in FIGURE 2 in which groove 46 interconnects ports 41 and 42 of the valve 35. Thus exhaust fluid pressure from the fluid motor 16 at port 41 will flow through groove 46 and port 42 into conduit 54 to the manually adjustable exhaust valve 36; During the spin cycle by manual adjustment of the exhaust valve 36 the fluid exhaust from the fluid motor 16 can be variably restricted and thus the speed .of the spinning of the clothes basket may be regulated by manual adjustment of valve 36. a As previously explained, over pressure development which may injure parts of the transmission is prevented by over pressure relief valve 23. 7

Referring to FIGURE 1, when the electric motor is stopped and then reversed to go into the agitate cycle as would be the case in an automatic washer through the operation of an electric timer switch mechanism, conduit 20 then becomes the fluid supply conduit or inlet conduit for pump 15 as it rotates in the direction indicated by the arrow labeled agitate. Conduit 20 will now draw fluid from the sump through check valve 56 to supply pump 15. When the fluid pressure is thus no longer supplied into conduit 20 pressure will no longer exist in port 39 a spin motor 50 is blocked and can only escape through port 40, conduit 52 and through restriction 53 to the sump.

Since the'exhaust fluid pressure conduit 50 from fluid motor 16 is now blocked from flowing to sump 19 except through restriction 53, the valve 35 acts as a stop valve or brake by substantially restricting the exhaust 7 from the fluid motor 16 and bringing the clothes basket to a stop quickly so that the automatic washer can continue into the next cycle. The valve spool 43 of valve 35 will stay in its position to the left until once more the pump is rotated in the direction labeled spin. 7

When the fluid pump is operated in the direction shown in FIGURE 1, fluid pressure willb'e supplied into'conduit 21 to the fluid circuit for agitate motor 17. Conduit 21 is connected by conduit 28 to over pressure relief valve 22 and if the fluid pressure in 21 exceeds a predetermined value, for example 200 p.s.i., the relief valve 22 will open and thereby connect conduit 28 to conduit 27. Thus the pressure will be bled oif into the inlet conduit 20 for the pump 15, thereby relieving the pressure until it is below the predetermined maximum.

Fluid pressure in conduit 21 is introduced into cylinder I V 139 moving piston 138 up to engage clutch teeth 136 and 137 and thus directly connect the .vane 76 of the agitator motor to drive the motor 12. Fluid pressure in conduit 21 will also be introduced into cylinder 126 to move piston 127 to the right to engage pawl teeth 128 with one of the notches in disc 129 to provide a positive brake on the clothes basket to hold it stationary while the agitator is oscillating. Fluid pressure in conduit 21 is also supplied to port 102 of direction valve 70.

In the position of valve 70 as illustrated in FIGURE 2, fluid pressure in port 102 will flow through groove into port 103, conduit 111 and port 81 into fluid chamber 75 of agitate motor 17. At this time port 82 of fluid chamber 75 is connected through conduit 110, port'106, port 105, conduit 112, and exhaust valve 71 to the sump thus exhausting pressure ahead of the vane 76 through port 82. Thus vane 76 will move counterclockwise to the position as illustrated in FIGURE 1 due to'the fluid pressure being introduced from port 81.

When vane 76 moves clockwise far enough to engage pin 78, pin 78 will move up pivoting arm 79 around pivot 90 and moving the valve spool 86 to its upper position illustrated in FIGURE 1 with the detent ball engaged in groove 93. In this upper position of the valve spool 86 fluid pressure will now be supplied from port 102 through groove 90 then port 101 into conduit and port 82 to fluid pressure chamber 75 to act on vane 76. Port 81 of the agitate motor 17 will now be connected by means of conduit 111, port 104, groove 91, port 105, conduit 112,

and exhaust valve 71 to the sump. Thus port 81 now'becomes the exhaust port of the agitate motor 17 and 82 is the pressure port.

Pressure supplied from port 82 will now act on vane 76 to move the vane clockwise. The vane 76 will move clockwise until it again engages pin 77 to rock arm 79 and move valve spool 86 to its lower position to repeat the above cycle.

As described, the fluid motor '17 acts to oscillate the agitator of the wash machine by fluid pressure oscillation,

of vane 76. The speed of agitation as in the case of the spin motor is controlled by means of manual'adjustment of exhaust valve 71. In either position of the valve spool is reversed the fluid pressure in fluid conduit 21 will be interrupted and fluid conduit 21 will again become the supply conduit for pump 15. Thus piston 127 of the brake 125 will be moved to a disengaged position by the spring 130 and the agitator clutch will be disengaged by spring 140.

Referring to FIGURE 3 the transmission is illustrated as installed in an automatic washer environment. The location of the major elements of the transmission such as pump 15, motor 16 and agitate motor 17 is indicated in FIGURE 3.

A main or low pressure housing 150 is provided for the transmission having a large cavity 151 therein which can be termed a low pressure cavity. The low pressure cavity 151 is enclosed by an end plate 152 which is secured to the housing 150 by suitable means such as bolts (not illustrated). Within the low pressure cavity 151, a high pressure housing 153 is provided which contains the transmission components of the washer. The housing 153 is secured to end plate 152 by bolts 154. A gasket 155 is provided between housing 153 and end plate 152 to provide a fluid seal for the housing 153. A gasket 156 is provided between housing 150 and end plate 152 to provide a fluid seal therebetween.

End plate 152 has a bore 160 therein to accommodate the driving shaft between motor 118 and pump 15. Housing 150 has a bore 160a therein to accommodate hollow shaft 11a and agitator drive shaft 134. The end plate further has an outwardly extending portion 161 which houses the clutch mechanism 135 operative to drivingly engage the agitator motor 17 with agitator shaft 134. The upper side of housing 153 as viewed in FIGURE 3 may be of unitary construction as a part of housing 153 or may be an end plate 162 suitably secured to housing 153 for example by bolts (not illustrated). End plate 162 is provided with bores 163 and 164. Bore 163 accommodates the hollow shaft 11a to drive the clothes basket 11 and the agitator drive shaft 134. Bore 164 has a projection 128 of the brake mechanism 125 slidable therein.

Housing 153 is a casting which would include Wall sections therein such as indicated at 165 to accommodate the components of the transmission. Indicated at 166 and located on the back side of the transmission as illustrated in FIGURE 3 provision is made for the control valves of the transmission.

Housing 153, end plate 162 and end plate 152 including the gasket 155 encloses a cavity which can be referred to as a high pressure cavity, generally indicated by the numeral 167. It can be seen that the high pressure fluid within the transmission will be contained by the housing 153, end plates 162 and 152 and gasket 155. Any oil which would leak from any of the transmission components within the housing 153 would leak into the low pressure cavity 151. The fluid within the low pressure cavity thus serves as a sump for the transmission and due to the seal between housing 150 and end plate 1152 including gasket 156, the oil in the low pressure cavity 151 is prevented from leaking out.

Thus a housing structure has been provided in which expensive sealing structures within housing 153 for main components of the transmission are not required since any oil leaking therefrom will be contained within a low pressure cavity which envelops the transmission.

In hydraulic transmissions of the known type, as may be used for example in an automatic washing machine, any oil leaks from the main transmission components would not be caught by an outer housing having a low pressure cavity and thus would be quite unacceptable if such a leak developed, in that oil would leak out onto the floor where the washing machine is located. The housing structure illustrated in FIGURE 3 thus is advantageous in that oil will not leak out of the wash machine onto the floor or surrounding area. Further, due to the use of a structure which would contain oil surrounding the transmission component-s, the transmission operates more quietly than is the case with known housing structures.

From the above it will be apparent that a new and improved transmission has been provided which is adaptable to drive the agitator and clothes basket of an automatic washer. Applicant has provided a single reversible pump rotatable in one direction to supply fluid to an agitate motor circuit and rotatable in the other direction to supply fluid to a spin motor circuit, thus eliminating the need for a special valve to control the direction of flow.

Further, the present invention provides a simple and economical means of controlling the speed of the spin motor and an agitate motor for a washing machine. With the use of manual valves 36 and 71 the speed of either the spinning of the clothes basket or the speed of the agitation of the agitator 12 may be manually controlled between broad limits. The present invention is advantageously adaptable to an automatic washing machine to provide an infinitely variable speed of agitation and an infinitely variable speed of the clothes basket during the spin cycle. Safely provisions have been included in the circuits using over pressure relief valves 22 and 23 to prevent build up of harmful pressures in the system.

The present invention also includes a spring urged stop valve 35 which will serve to automatically stop the clothes basket after the spin cycle by using the spin fluid motor itself as a brake on the clothes basket.

Economies will result due to the use of a single pump operable in either direction of rotation to operate in one direction the spin motor and in the other direction an agitator motor. Due to the use of a positive displacement pump and a positive displacement motor with control means of a variable restricted exhaust expensive variable volume pumps or variable volume motors are unnecessary. Further, the clutch to connect the agitator to the agitator motor is automatically engaged when pressure is induced in the agitate circuit as is the fluid actuated brake for holding the clothes basket stationary.

Various features of the invention have been particularly shown and described; however, it should be obvious to one skilled in the art that vaarious modifications may be made therein without departing from the scope of the invention.

I claim:

1. In a hydraulic transmission having selectively operable output members comprising a first output element and a second output element, a sump for hydraulic fluid, a fluid pump connected to said sump, said pump being connected to supply fluid pressure to a first fluid circuit to drive said first output member when said pump is rotated in one direction of rotation and to supply fluid pressure to a second fluid circuit to drive said second output member when said pump is rotated in a reverse direction, said first fluid circuit including a first hydraulic motor connected to said first output member and hydraulically connected to said pump, an exhaust conduit for said first motor, a first selectively operable valve in said exhaust conduit adapted to variably restrict exhaust pressure from said motor to thereby control the speed of drive of said first output member, said second fluid circuit including a second fluid motor connected to drive said second output member and hydraulically connected to said pump, an exhaust conduit for said second fluid motor, a second selectively operable valve in said exhaust conduit for said second motor adapted to variably restrict exhaust fluid pressure from said second motor and thereby control the speed of drive of said second output member.

2. A hydraulic transmission as claimed in claim 1 including additional valve means in said exhaust conduit between said first hydraulic motor and said selectively operable valve adapted to at times interrupt the connection between said motor and said selectively operable valve.

3. A hydraulic transmission as claimed in claim 2 7v wherein said additional valve means isadapted to interrupt the connection between said first hydraulic motor and said selectively operable valve when said pump is supplying fluid pressure to said second hydraulic motor whereby said first hydraulic motor will serve as a hydraulic brake for said first output element.

4. A hydraulic transmission as claimed in claim 3 wherein said additional valve means includes a valve spool connected to said first circuit whereby fluid pressure in said first circuit urges said valve spool to a position hydraulically connecting said exhaust conduit to said first selectively operable valve and spring means urging said spool to a position interrupting said hydraulic 7 connection when no fluid pressure exists in said first circuit.

5. In a hydraulic transmission having selectively operable output members comprising a first output member and a second member, a sump having hydraulic fluid 5 therein, a reversible fluid pump connected to said sump, said pump'being connected to supply fluid pressure to a first fluid circuit to rotate said first output member when said pump is rotated in one direction and to supply fluid pressure to a second fluid circuit to oscillate said second output member when said pump is rotated in the 7 reverse direction, said first fluid circuit including a rotary hydraulic motor connected to said first output member and hydraulically connected to said pump, an exhaust conduit for said rotary motor, a first selectively operable valve in said exhaust conduit adapted to variably restrict exhaust pressure from saidrotary motor to thereby control the speed of rotation of said first output member, said second fluid circuit including an oscillating fluid motor connected to oscillate said second output member and hydraulically connected to said pump, an exhaust conduit for said oscillating fluid motor, and a second selectively operable valve in said exhaust conduit adapted to variably restrict exhaust fluid pressure from said oscillating fluid motor and thereby control the speed of oscillation of said second output member.

' 6. A hydraulic transmission as claimed in claim 5 including additional valve means in said exhaust conduit for said rotary hydraulic motor adapted to at times interrupt the connection between said rotary motor and said' first selectively operable valve.

7. Ahydraulical transmission as claimed in claim 6 wherein said additional valve means will interrupt said connection when said pump is supplying fluid pressure to a said oscillating fluid motor whereby said rotary hydraulic motor will serve as a hydraulic brake for said first output member.

8. A hydraulic transmission as claimed in claim 7 wherein said additional valve means includes a valve spool connected to said first circuit whereby fluid pressure in said .first circuit urges said valve spool to a position hydraulically connecting said exhaust conduit to said first selectively operable valve and spring means urging said spool to a position interrupting said hydraulic connection when no fluid pressure exists in said first circuitJ 9. In a hydraulic transmission for an automatic washer having a clothes tub and anagitator, a sump having hy draulic fluid therein, a reversible fluid pump connected to said sump, said pump being connected to supplyfluid pressure to a first fluid circuit to rotate said clothes tub when said pump is rotated in one direction and to sup ply fluid pressure to a second fluid circuit to oscillate said agitator when said pump is rotated in the reverse direction, said first fluid circuit including a rotary hydraulic motor connected to said clothes tub and hydraulically motor connected to said pump, an exhaust conduit for said rotary motor, a first selectively operable valve in said exhaust conduit adapted to variably restrict exhaust pressure from said rotary motor to thereby control the speed of rotation of said clothes tub, said second fluid circuit including an oscillating fluid motor connected to oscillate said agitator and hydraulically connected to said pump, an exhaust conduit for said oscillating fluid motor, and a second selectively operable valve in said,

exhaust conduit adapted to variably restrict exhaust fluid pressure from said oscillating fluid motor and thereby control the speed of oscillation of said agitator.

10. A hydraulic transmission as claimed in claim 9 including additional valve means in said exhaust conduit between said rotary hydraulic motor and said first selectively operable valve, said additional valve means being adapted to interrupt the connection between said rotary hydraulic motor and said first selectively operable valve when said pump is supplying fluid pressure to said second fluid circuit to oscillate said agitator motor will serve as a hydraulic brake for said clothes tub.

References Cited UNITED STATES PATENTS WILLIAM I. PRICE, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,330,138 July ll, 1967 George E Flinn It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 7, line 18, after "second" insert output Column 8, line 16, cancel "motor".

Signed and sealed this 14th day of October 1969,

(SEAL) Attest:

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer WILLIAM E. SCHUYLER, JR. 

1. IN A HYDRAULIC TRANSMISSION HAVING SELECTIVELY OPERABLE OUTPUT MEMBERS COMPRISING A FIRST OUTPUT ELEMENT AND A SECOND OUTPUT ELEMENT, A SUMP FOR HYDRAULIC FLUID, A FLUID PUMP CONNECTED TO SAID SUMP, SAID PUMP BEING CONNECTED TO SUPPLY FLUID PRESSURE TO A FIRST FLUID CIRCUIT TO DRIVE SAID FIRST OUTPUT MEMBER WHEN SAID PUMP IS ROTATED IN ONE DIRECTION OF ROTATION AND TO SUPPLY FLUID PRESSURE TO A SECOND FLUID CIRCUIT TO DRIVE SAID SECOND OUTPUT MEMBER WHEN SAID PUMP IS ROTATED IN A REVERSE DIRECTION, SAID FIRST FLUID CIRCUIT INCLUDING A FIRST HYDRAULIC MOTOR CONNECTED TO SAID FIRST OUTPUT MEMBER AND HYDRAULICALLY CONNECTED TO SAID PUMP, AN EXHAUST CONDUIT FOR SAID FIRST MOTOR, A FIRST SELECTIVELY OPERABLE VALVE IN SAID EXHAUST CONDUIT ADPATED TO VERIABLY RESTRICT EXHAUST PRESSURE FROM SAID MOTOR TO THEREBY CONTROL THE SPEED OF DRIVE OF SAID FIRST OUTPUT MEMBER, SAID SECOND FLUID CIRCUIT INCLUDING A SECOND FLUID MOTOR CONNECTED TO DRIVE SAID SECOND OUTPUT MEMBER AND HYRAULICALLY CONNECTED TO SAID PUMP, AN EXHAUST CONDUIT FOR SAID SECOND FLUID MOTOR, A SECOND SELECTIVELY OPERABLE VALVE IN SAID EXHAUST CONDUIT FOR SAID SECOND MOTOR ADAPTED TO VARIABLY RESTRICT EXHAUST FLUID PRESSURE FROM SAID SECOND MOTOR AND THEREBY CONTROL THE SPEED OF DRIVE OF SAID SECOND OUTPUT MEMBER. 